On Sun, 10 Aug 2008 21:26:18 -0700
Jeremy Fitzhardinge <jeremy@goop.org> wrote:

quoted text
> Nick Piggin wrote:
> > Nice debugging work.
> >
> > I'd suggest something like the attached (untested) patch as the
> > simple fix for now.
> >
> > I expect the benefits from the less synchronized,
> > multiple-in-flight-data global queue will still outweigh the costs
> > of dynamic allocations. But if worst comes to worst then we just go
> > back to a globally synchronous one-at-a-time implementation, but
> > that would be pretty sad! 
> 
> What if we went the other way and strictly used queue-per-cpu?  It
> means multicast would require multiple enqueueing operations, which
> is a bit heavy, but it does make dequeuing and lifetime management
> very simple...

as long as send-to-all is still one apic operation.. otherwise it gets
*really* expensive....
(just think about waking all cpus up out of their C-states.. one by one
getting the full exit latency sequentially)

-- 
If you want to reach me at my work email, use arjan@linux.intel.com
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
--
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/